1. Field of the Invention
This invention relates to a toner and toner particles for electrophotography, and more particularly to a toner and toner particles for electrophotography comprising a coloring agent and a fluorine-contained graft copolymer, which have the image-fixing property suitable for development and image fixing at high speed, do not give rise to an off-set phenomenon, and have high blocking resistance.
2. Discussion of Background
Technique of electrophotography which has long been applied to a copying machine is now extensively utilized for a laser beam-type printer which can achieve high-speed recording. A thermal roller capable of fixing images at high speed is also widely employed these days as an image fixing apparatus. Thus, attention is now focused on high-speed recording.
In addition, high image-fixing ability is strongly demanded in order to satisfy recent various requirements. For example, images are now required to be reproduced or printed on a sheet of paper, such as an envelope for direct mail, which is to be folded at the time when it is used, and on a sheet of paper, such as a post card, which is thicker than ordinary paper.
In order to meet the above requirements, a toner for electrophotography which comprises as its binder a styrene-acryl copolymer resin has been proposed in Japanese Laid-Open Patent Application 50-134652. The toner has a degree of dispersion of 3.5 to 4.0, and hardly give rise to the off-set phenomenon.
Furthermore, a resin composition for a toner for electrophotography has been proposed in Japanese Laid-Open Patent Application 62-115170. This resin composition is composed of styrene-acrylic acid copolymer resins A and B, each having a weight average molecular weight of 10,000 to 30,000 and 200,000 to 400,000, and a glass transition temperature of 60 to 70.degree. C. and 55 to 65.degree. C. The blend ratio (weight basis) of resin A to resin B is 90/10 to 50/50. The melt viscosity at 140.degree. C. of the resin composition is 10,000 ps or less.
Besides the above, some toners have been proposed, which have the image-fixing property suitable for development and image fixing at high speed, do not give rise to the off-set phenomenon, and have high blocking resistance.
However, the conventional toners for electrophotography still have some disadvantages. For example, in the case of a wet type, the toner cannot be stably dispersed in an aliphatic hydrocarbon solvent. In the case where the conventional dry-type toner is employed, images cannot be satisfactorily fixed when fixing energy is low. Thus, a satisfactory toner does not exist so far.